Hi all,

I'm experiencing a persistent rattling noise coming from the cab, which I initially thought was inside the dash. However, the sound disappears when I switch to 2Hi.

Seems like my 4wd system has started acting up. When I pull away from a stop position, the front end makes a crunching sound as the car edges forward. At first, I thought it was just the wheels compacting powdery snow, but there's no sound at all in 2Hi.

As I pull away, the car feels slightly jerky with the crunching sounds, though not too severe. Once the truck gets going, the crunching sounds and jerkiness from the front end stop, but the rattling sound in the cab continues.

There's no noise at all when the truck isn't moving or rev'd in park.

I've got a poor alignment, so I'm wondering if it's sending incorrect traction signals to the 4WD system. I'm planning to check the oil levels in the transfer case later today.

Has anyone else experienced a similar issue? I haven't found much information on this particular problem.

Cheers

 

Be sure to eliminate any other sources of this noise. Are you familiar with the noise of a bad CV joint? Although I would normally think a bad CV joint would sound bad irrespective of being in 2wd or 4wd.

Another possibility is the spline engagement mechanism for the front axle. This is what connects the right axle to the differential and is controlled by a vacuum actuator located under the battery tray, at least it is located there in my 99. If the spline is damaged or the gear it engages is damaged, I think there can be a grinding sound. I've never had this happen, only heard of this. The mechanism I'm describing is associated with parts 10 to 24 on the exploded parts diagram here: https://nemigaparts.com/cat_spares/e...t/06/tt06-089/